Polyaxial screw and locking cap

ABSTRACT

Systems, methods, and devices for securing a spinal rod are provided. A clamp assembly comprises a tulip comprising an opening comprising an inner surface, wherein the inner surface is threaded; and a threaded locking cap disposed in the opening, wherein threads of the locking cap and the inner surface include various geometries.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. patent application Ser. No. 16/707,329 filed on Dec. 9, 2019, which is incorporated in its entirety herein.

BACKGROUND

Many types of spinal irregularities cause pain, limit range of motion, or injure the nervous system within the spinal column. These irregularities can result from trauma, tumor, disc degeneration, or disease. Typically, these irregularities are treated by immobilizing a portion of the spine. This treatment typically involves affixing a plurality of components, such as, for example, screws, hooks, and/or clamps, to one or more vertebrae, and attaching the components to an elongated rod that stabilizes the vertebrae.

SUMMARY

In an exemplary embodiment, the present disclosure provides a clamp assembly comprising a tulip comprising an opening comprising an inner surface, wherein the inner surface is threaded; and a threaded locking cap disposed in the opening, wherein threads of the locking cap and the inner surface include various geometries.

In another exemplary embodiment, the present disclosure provides a clamp assembly comprising a tulip comprising an opening comprising an inner surface, wherein the inner surface is threaded; and a threaded locking cap disposed in the opening, wherein the threaded locking cap includes a drive feature, wherein the drive feature includes various geometries.

In another exemplary embodiment, the present disclosure provides a clamp assembly comprising a tulip, wherein an inner surface of the tulip comprises threads; and a drive feature positioned in an outer portion of the tulip, the drive feature configured to receive a driving instrument, wherein the drive feature includes various geometries.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory in nature and are intended to provide an understanding of the present disclosure without limiting the scope of the present disclosure. In that regard, additional aspects, features, and advantages of the present disclosure will be apparent to one skilled in the art from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

These drawings illustrate certain aspects of some of the embodiments of the present disclosure and should not be used to limit or define the disclosure.

FIG. 1 illustrates a clamp assembly in accordance with particular embodiments of the present disclosure;

FIG. 2 illustrates square threads of a clamp assembly in accordance with particular embodiments of the present disclosure;

FIG. 3A illustrates a first type of buttress threads of a clamp assembly in accordance with particular embodiments of the present disclosure;

FIG. 3B illustrates a second type of buttress threads of a clamp assembly in accordance with particular embodiments of the present disclosure;

FIG. 3C illustrates a bottom positive angle thread of a clamp assembly in accordance with particular embodiments of the present disclosure;

FIG. 4A illustrates a top view of a drive feature of a threaded locking cap in accordance with particular embodiments of the present disclosure;

FIG. 4B illustrates a top view of another drive feature of a threaded locking cap in an initial position in accordance with particular embodiments of the present disclosure;

FIG. 5 illustrates a side cross-sectional view of another threaded locking cap and driving instrument in accordance with particular embodiments of the present disclosure;

FIG. 6 illustrates a side cross-sectional view of another threaded locking cap and insertion instrument in accordance with particular embodiments of the present disclosure;

FIG. 7 illustrates a side view of a clamp assembly in accordance with particular embodiments of the present disclosure;

FIG. 8 illustrates a side view of another clamp assembly in accordance with particular embodiments of the present disclosure;

FIG. 9 illustrates a side cross-sectional view of another clamp assembly in accordance with particular embodiments of the present disclosure;

FIG. 10 illustrates a side view of another clamp assembly in accordance with particular embodiments of the present disclosure;

FIG. 11 illustrates a side view of another locking cap in accordance in accordance with particular embodiments of the present disclosure;

FIG. 12 illustrates a portion of another locking cap in accordance with particular embodiments of the present disclosure;

FIG. 13 illustrates a clamp assembly in accordance with particular embodiments of the present disclosure;

FIG. 14 illustrates a tulip in accordance with particular embodiments of the present disclosure;

FIG. 15 illustrates another tulip in accordance with particular embodiments of the present disclosure;

FIG. 16A illustrates a side cross-sectional view of a clamp assembly in accordance with particular embodiments of the present disclosure;

FIG. 16B illustrates a side cross-sectional view of another clamp assembly in accordance with particular embodiments of the present disclosure;

FIG. 16C illustrates a side cross-sectional view of another clamp assembly in accordance with particular embodiments of the present disclosure;

FIG. 17A illustrates a tulip in accordance with particular embodiments of the present disclosure;

FIG. 17B illustrates a saddle in accordance with particular embodiments of the present disclosure;

FIG. 18 illustrates a side cross-sectional view of another clamp assembly in accordance with particular embodiments of the present disclosure;

FIG. 19A illustrates a side cross-sectional view of another clamp assembly in accordance with particular embodiments of the present disclosure;

FIG. 19B illustrates a perspective view of a saddle in accordance with particular embodiments of the present disclosure;

FIG. 20A illustrates a bottom view of a tulip in accordance with particular embodiments of the present disclosure;

FIG. 20B illustrates a bottom view of a tulip with a bone screw in accordance with particular embodiments of the present disclosure;

FIG. 21A illustrates a clamp assembly with a bone screw in accordance with particular embodiments of the present disclosure;

FIG. 21B illustrates a bone screw in accordance with particular embodiments of the present disclosure;

FIG. 22A illustrates a perspective view of a clamp assembly with a pivoting bone screw in accordance with particular embodiments of the present disclosure;

FIG. 22B illustrates a side cross-sectional view of a clamp assembly with a bone screw in accordance with particular embodiments of the present disclosure;

FIG. 23 illustrates a one-piece tulip and bone screw in accordance with particular embodiments of the present disclosure;

FIG. 24A illustrates a side cross-sectional view of a clamp assembly in accordance with particular embodiments of the present disclosure;

FIG. 24B illustrates a top view of a head of a bone screw in accordance with particular embodiments of the present disclosure;

FIG. 25A illustrates a portion of an inner surface of a tulip in accordance with particular embodiments of the present disclosure;

FIG. 25B illustrates a portion of an inner surface of another tulip in accordance with particular embodiments of the present disclosure;

FIGS. 26A-26K illustrate various geometries of an upper portion of a tulip in accordance with particular embodiments of the present disclosure;

FIGS. 27-29 illustrate various features positioned on an outer surface of a tulip in accordance with particular embodiments of the present disclosure;

FIG. 30 illustrates a clamp assembly with break off portions in accordance with particular embodiments of the present disclosure;

FIG. 31A illustrates a clamp assembly with a cable in accordance with particular embodiments of the present disclosure; and

FIG. 31B illustrates a tulip with a cable positioned about a spinal rod in accordance with particular embodiments of the present disclosure.

DETAILED DESCRIPTION

For the purpose of promoting an understanding of the principles of the present disclosure, reference will now be made to the implementations illustrated in the drawings and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the disclosure may be intended. Any alterations and further modifications to the described devices, instruments, methods, and any further application of the principles of the present disclosure are fully contemplated as would normally occur to one skilled in the art to which the disclosure relates. In particular, it may be fully contemplated that the features, components, and/or steps described with reference to one or more implementations may be combined with the features, components, and/or steps described with reference to other implementations of the present disclosure. For simplicity, in some instances the same reference numbers are used throughout the drawings to refer to the same or like parts.

Embodiments generally relate to spinal surgery. More particularly, embodiments relate to systems, methods, and devices for securing a spinal rod and a pedicle screw with a clamp assembly.

The clamp assembly can be utilized for open and percutaneous approaches to the posterior spine. The clamp assembly can be used on multiple types of pedicle screws such as polyaxial, uniplanar, monoaxial, reduction, and modular pedicle screws. The clamp assembly locks or restricts motion of the pedicle screw and the spinal rod. This allows corrective forces to transfer to vertebra for axial derotation, parallel compression, parallel distraction, and/or reduction.

FIG. 1 illustrates a clamp assembly (“clamp assembly”) 100 in accordance with particular embodiments of the present disclosure. In the illustrated embodiment, the clamp assembly 100 may include a tulip 102 and a threaded locking cap 114 disposable in the tulip 102. A pedicle screw 115 may extend from a bottom portion of the tulip 102. As illustrated, a spinal rod 118 may be held by the tulip 102. By tightening the threaded locking cap 114 into the tulip 102, a spinal rod 118 and pedicle screw 115 may be secured in the tulip 102.

The tulip 102 may be a rigid member that resembles a bullet with a hollow interior. The tulip 102 may include an opening 104 situated between portions 106 a and 106 b. A curved portion 108 may be disposed between the portions 106 a and 106 b, as shown. The curved portion 108 may be curved to correspond with a shape of a spinal rod 118. As illustrated, the portions 106 a and 106 b may be in the form of tabs that extend generally parallel away from the curved portion 108 to distal ends 110 a and 110 b. In certain embodiments, the opening 104 may be defined between the portions 106 a and 106 b. In certain embodiments, the opening 104 may extend from the curved portion 108 to distal ends 110 a and 110 b of the portions 106 a and 106 b, as shown. Inner surface 112 of the portions 106 a and 106 b may be threaded.

The threaded locking cap 114 may be disposed within the opening 104, as shown. The spinal rod 118 may extend through the opening 104, and a screw such as the pedicle screw 115 may extend through the curved portion 108. As illustrated, the pedicle screw 115 (or a portion thereof, such as the screw head) may extend into the curved portion 108 of the tulip 102. In accordance with particular embodiments, tightening the threaded locking cap 114 should a saddle component when then compresses against the pedicle screw 115 to restrict motion of the spinal rod 118 and the pedicle screw 115 thereby forming a rigid construct.

Various thread geometries can be used for the inner surface 112 of the tulip 102 and the threaded locking cap 114. Suitable thread geometries may include, but are not limited to, rectangular shaped threads and/or angled threads. FIGS. 2, 3A, 3B, and 3C will describe different thread geometries in accordance with particular embodiments.

FIG. 2 illustrates threads 200 of the inner surface 112 and threads 202 of the threaded locking cap 114 in accordance with particular embodiments of the present disclosure. As shown, the threads 200 and 202 are straight or rectangular shaped (e.g., square shaped).

FIG. 3A illustrates threads 300 a (e.g., buttress threads) of an inner surface 112 a and threads 302 a of a threaded locking cap 114 a in accordance with particular embodiments of the present disclosure. As shown, a bottom surface 304 a of a thread 302 a may be angled outward away from a minor diameter 306 a. A top surface 308 a may be flat or angled inward (e.g., top surface 308 b shown on FIG. 3B), towards the minor diameter 306 a.

FIG. 3B illustrates threads 300 b (e.g., buttress threads) of an inner surface 112 b and threads 302 b of a threaded locking cap 114 b in accordance with particular embodiments of the present disclosure. As shown, a bottom surface 304 b of a thread 302 b may be angled outward away from a minor diameter 306 b. A top surface 308 b may be flat or angled inward towards the minor diameter 306 b.

FIG. 3C illustrates threads 300 c of an inner surface 112 c and threads 302 c of a threaded locking cap 114 c in accordance with particular embodiments of the present disclosure. As shown, a bottom surface 304 c of a thread 302 c may be angled inward to a minor diameter 306 c. A top surface 308 c may angled inward or flat.

In accordance with present embodiments, a driving instrument (e.g., driving instrument 500 on FIG. 5 or driving instrument 602 on FIG. 6 ) may be used to drive the locking cap 114 into the tulip 104. The locking cap 114 may be include various design features for engagement with the driving instrument. FIGS. 4A and 4B illustrate various drive features on the locking cap 114 into which the driving instrument may be inserted in accordance with particular embodiments. FIGS. 5 and 6 illustrate various features that may be used for retainment of the locking cap 114 by the driving instrument in accordance with particular embodiments. The locking cap 114 may also include various features for contact with the tulip 104. FIGS. 7 to 11 illustrate various features of the locking cap 114 for contact with the tulip 104.

FIG. 4A illustrates a locking cap drive feature (“drive feature”) 400 a for a locking cap 114 d, in accordance with particular embodiments of the present disclosure. The drive feature 400 a may be used to insert and tighten the locking cap 114 d, and may be a hex, a hexalobe (as shown), or a modified hexalobe (e.g., shown on FIG. 4B). The drive feature 400 a may either go partway into or through the locking cap 114 d. The drive feature 400 a may be formed in a top of the locking cap 114 d. In the illustrated embodiment, the drive feature 400 a is recessed, but it should be understood the drive feature 400 a may also be a protrusion from the locking cap 114 d.

FIG. 4B illustrates a locking cap drive feature (“drive feature”) 400 b for a locking cap 114 e, in accordance with particular embodiments of the present disclosure. The drive feature 400 b may be used to insert and tighten the locking cap 114 e, and may be a hex, a hexalobe, or a modified hexalobe (as shown). The modified hexalobe has inner lobes 402 of a hexalobe truncated by a circle. The drive feature 400 b may either go partway into or through the locking cap 114 e. The drive feature 400 b may be formed in a top of the locking cap 114 e. In the illustrated embodiment, the drive feature 400 b is recessed, but it should be understood the drive feature 400 a may also be a protrusion from the locking cap 114 e.

FIG. 5 illustrates a cross-section of a driving instrument 500 positioned within a locking cap 114 f in accordance with particular embodiments of the present disclosure. As shown, the locking cap 114 f may include grooves 501 to receive spring tabs 502 of a driving instrument 501. The spring tabs 502 may clip into the grooves 500 of the locking cap 114 f, for example, to secure the driving instrument 500 to the locking cap 114 f In certain embodiments (not shown), the locking cap 114 f can be retained instead by a tapered drive feature on either the locking cap 114 f, the driving instrument 501, or both.

FIG. 6 illustrates a cross-section of a split ring 600 housed on a driving instrument 602 in accordance with particular embodiments of the present disclosure. The split ring 600 may be used, for example, to secure the driving instrument 602 to the locking cap 114 g. As shown, the split ring 600 may exert radial pressure against a drive feature 604 of a locking cap 114 g to retain the locking cap 114 g. In certain embodiments, a groove (not shown) may be cut into the the drive feature 604 for the split ring 600 to expand into for further retention. The locking cap 114 g may include a flat bottom 606, as shown.

FIG. 7 illustrates a locking cap 114 h disposed within the tulip 102, in accordance with particular embodiments of the present disclosure. As shown, a bottom 700 of the locking cap 114 h may be flat but have a narrower outer diameter 701 than a minor diameter 702 of threads 703, to provide a more consistent contact with a curvature of the spinal rod 118. However, while FIG. 7 shows the bottom 700 as being flat, it should understood that embodiments of the bottom 700 may be otherwise formed, for example, curved or angled.

FIG. 8 illustrates a locking cap 114 i disposed within the tulip 102, in accordance with particular embodiments of the present disclosure. As shown, a bottom 800 of the locking cap 114 i may have a rounded bump 802 to contact the spinal rod 118 at a point 804. The bump 802 may deform or indent the spinal rod 118 or be deformed by the spinal rod 118 to increase grip. The bump 802 may extend from a minor portion of the bottom 800 of the locking cap 114 i.

FIG. 9 illustrates a cross-section of a locking cap 114 j disposed within a tulip 102, in accordance with particular embodiments of the present disclosure. A bottom 900 of the locking cap 114 j may have a rounded ring 900 to contact the spinal rod 118 at two points 902 and 904. The rounded ring 900 may deform or indent to increase grip. In some embodiments, the rounded ring 900 may be raised portion of the bottom 900 of the locking cap 114 j.

FIG. 10 illustrates a locking cap 114 k disposed within the tulip 102 in accordance with particular embodiments of the present disclosure. A bottom 1000 of the locking cap 114 k may have a groove 1002 cut into it that seats on the spinal rod 118 as the locking cap 114 k rotates to its final tightening state. The groove 1002 may have profile, for example, the matches a profile of the spinal rod 118.

FIG. 11 illustrates a locking cap 114L in accordance with particular embodiments of the present disclosure. As shown, a contact surface 1100 for the spinal rod 118 (e.g. shown on FIG. 10 ) is a separate component to allow the contact surface 1100 to be made from a different material or surface finish from the locking cap 114L. As illustrated, the contact surface 1100 may be attached to a bottom of the locking cap 114L. The contact surface 1100 may be shaped to any of the previously described embodiments. Any suitable technique may used for attachment of the contact surface 1100 to the locking cap 114L, including, but not limited to, adhesives, welding, locking features, and/or fasteners, among others.

Additional features may be included on the locking cap 114. For example, features may be included on the locking cap that increase engagement of the locking cap 114 with the tulip 114 more efficient for installation. FIGS. 12 and 13 illustrate different features that may be included on the locking cap 114 for increasing engagement with the tulip 104.

FIG. 12 illustrates a portion of a locking cap 114 m in accordance with particular embodiments of the present disclosure. As shown, a first thread 1204 at a bottom 1202 of the locking cap 114 m is broken by a radiused cut 1200 The radiused cut 1120 from the first thread 1200 may increase the strength of the first thread 1200 as it is being engaged and to prevent cross-threading of the locking cap 114 m.

FIG. 13 illustrates a clamp assembly 1300 in accordance with particular embodiments of the present disclosure. A start 1302 of threads 1304 in a locking cap 114 n and a start 1306 of threads 1308 in an inner surface 112 d of a tulip 1310 are timed with corresponding markings such as, for example, cutouts 1303 of the locking cap 114 n and marking 1310 of the tulip 1310. When the markings/cutouts 1303 and 1310 are aligned, the start 1302 of the threads 1304 on the locking cap 114 n is close to engaging the start 1306 of the threads 1308 on the inner surface 112 d of the tulip 1310. This allows a user to quickly and repeatably engage the threads 1304 of the locking cap 114 n with the inner surface 112 d of the tulip 1310. The tulip 1310 may have a rounded slot 1312 to accept the spinal rod 118 such that the spinal rod 118 is perpendicular to the threads 1304 of the locking cap 1302.

FIG. 14 illustrates the tulip 1310 in accordance with particular embodiments of the present disclosure. The sides 1400 of the tulip 1310 may be shaped as a concentric cylinder which taper towards the bottom 1402 of the tulip 1310. A front side 1404 and back side (not shown) are flat, with an upper flat portion 1406 being narrower in width than a lower flat portion 1408.

FIG. 15 illustrates a tulip 1500 in accordance with particular embodiments of the present disclosure. The tulip 1500 may be similar to the tulip 1310 as shown on FIG. 14 . The tulip 1500 may include a large radii or flat portion 1502 on a side 1504 of the tulip 1500. The flat portion 1502 may improve alignment with mating instruments (not shown).

FIG. 16A illustrates a cross-section of a clamp assembly 1600 a in accordance with particular embodiments of the present disclosure. The clamp assembly 1600 a may include a tulip 1602, a spherical head 1604 of a bone screw, and a saddle 1606.

The saddle 1606 may be movably disposed within an opening 1607, as shown. The saddle 1606 may be an elongated rigid member with a shape similar to the tulip 1602. The saddle 1606 includes an opening 1608 at a first end 1610 and an opening 1612 positioned opposite to the opening 1608 at a second end 1614, as shown. The saddle 1606 may include a ridge 1616 that projects into a recess 1618 extending along an inner surface 1620 of the tulip 1602, thereby preventing movement of the saddle 1606 beyond the recess 1618, as shown. The bone screw 1604 may be disposed within the tulip 1602 and the opening 1612. The opening 1612 may include curvature that corresponds with the shape of the spherical head 1604 to facilitate securing of the spherical head 1604 within the clamp assembly 1600 a, as shown. An internal taper 1619 of the tulip 1602 may retain the spherical head 1604. The polyaxial motion is locked when the spinal rod 118 (e.g., shown on FIG. 13 ) compresses into the saddle 1606 which compresses against the spherical head 1604 of the bone screw.

FIG. 16B illustrates a cross-section of a clamp assembly 1600 b and a clip 1620 in accordance with particular embodiments of the present disclosure. The clip 1620 may be used to retain the spherical head 1604 within the tulip 1602 instead of the internal taper 1619 (shown on FIG. 16A) of the tulip 1602. The clip 1620 may be disposed within an internal recess 1621 of the tulip 1602.

FIG. 16C illustrates a cross-section of a clamp assembly 1600 c with circumferential lips 1622 in accordance with particular embodiments of the present disclosure. To create a ring of contact between a saddle 1606 a and the spherical head 1604, one or more circumferential lips 1622 on the saddle 1606 a or an internal taper 1624 of the saddle 1606 a may contact the spherical head 1604.

FIGS. 17A and 17B illustrate a tulip 1700 and a saddle 1704 in accordance with particular embodiments of the present disclosure. The spherical head 1604 (shown on FIG. 16C) of the bone screw may be inserted into the tulip 1700 and the clip 1620 (shown on FIG. 16B) may be inserted into an internal groove 1702 of the head to retain the spherical head 1604. The saddle 1704 (shown on FIG. 17B) is then inserted from a top 1701 of the tulip 1700 with a spinal rod slot 1706 b 90° out of alignment with the rod slot of the tulip 1706 a. The saddle is then rotated into the internal groove 1702 so that the rod slots 1706 a and 1706 b are aligned. An upper profile (e.g., an upper profile 1708 shown on FIG. 17B) of the saddle 1704 and the internal groove 1702 are elliptically shaped to prevent the saddle 1704 from rotating out of alignment. Relief cuts 1710 in the tulip 1700 allow rotation of the saddle 1704 into alignment only in one direction. Grooves 1712 cut into the saddle 1704 allow for an interface with an assembly tool (not shown) to facilitate rotation.

FIG. 18 illustrates a cross-section of a clamp assembly 1800 including the tulip 1700 in accordance with particular embodiments of the present disclosure. In this embodiment, the saddle 1704 may be inserted into the tulip 1700 from the bottom 1808 and pressed past a retaining bump 1806. The spherical head 1604 of the bone screw is then inserted from a bottom 1808 of the tulip 1700 into contact with the saddle 1704 and the clip 1620 inserted from the bottom 1808 to retain the spherical head 1604. The saddle 1704 is then pressed down past the retaining bump 1806. The retaining bump 1806 and elliptical shape of the saddle 1704 and the internal groove 1702 prevent the saddle 1704 from moving upward and rotating.

FIG. 19A illustrates a clamp assembly 1900 in accordance with particular embodiments of the present disclosure. The clamp assembly 1900 may be similar to the clamp assembly 1800. In this embodiment, instead of an ellipse, internal flat portions 1901 of the tulip 1902 are positioned on either side of flat portions 1903 (also shown on FIG. 19B) of a saddle 1904 to restrict rotation of the saddle 1904 within the spinal rod slot 1906.

FIG. 19B illustrates the saddle 1904 in accordance with particular embodiments of the present disclosure. The saddle 1904 includes the flat portions 1903 to correspond with the flat portions 1901 of the tulip 1902 (shown on FIG. 19A).

FIG. 20A illustrates a bottom 2000 of a tulip 2002 in accordance with particular embodiments of the present disclosure. In this embodiment, a screw 2004 (shown on FIG. 20B) is inserted from a top (e.g., the top 1701 shown on FIG. 17A) of the tulip 2002 until it contacts an internal tapered portion 2006 at the bottom 2000. A saddle (e.g., the saddle 1904 shown on FIG. 19B) may then be inserted from the top of the tulip 2002 and rotated into alignment with a spinal rod slot (e.g., similar to the spinal rod slot 1706 a shown on FIG. 17A). Threads 2008 cut into the taper portion 2006 are shaped to allow the largest screw possible to thread through the tulip 2002.

FIG. 20B illustrates the bottom 2000 of the tulip 2002 with the screw 2004 in accordance with particular embodiments of the present disclosure. The screw 2004 extends through a passage 2010 positioned through the bottom 2000 of the tulip 2002.

FIGS. 21A and 21B illustrate a bone screw 2100 in accordance with particular embodiments of the present disclosure. The spherical head 1604 of the bone screw 2100 may be inserted into the tulip 2102 before being assembled to the threaded portion 2104 of the bone screw 2100. The threaded portion 2104 of the bone screw 2100 may be retained in the spherical head 1604 by a snap retaining fit, a press fit, a pin, threads, or some combination of retaining features (e.g., retaining feature 2106).

FIG. 21B illustrates the spherical head 1604 separated from the threaded portion 2104 of the bone screw 2100 in accordance with particular embodiments of the present disclosure. The threaded portion 2104 of the bone screw 2100 may be retained in the spherical head 1604 by a snap retaining fit, a press fit, a pin, threads, or some combination of retaining features (e.g., retaining feature 2106).

FIG. 22A illustrates a clamp assembly 2200 in accordance with particular embodiments of the present disclosure. The tulip 2202 may be a uniplanar tulip and may include a uniplanar screw 2204. The uniplanar tulip 2202 may have a through hole 2206 which contacts pivots (e.g., pivots 2207 shown on FIG. 22B) on the head of the screw 2204 and allows the head 2208 to pivot either along a spinal rod slot 2210 or perpendicular to the spinal rod slot 2210 depending on the orientation of the through hole 2206. A saddle 2208 compresses against the head 2208 when locked, restricting motion.

FIG. 22B illustrates a cross-section of the clamp assembly 2200, taken along a dashed line extending between A and A′, in accordance with particular embodiments of the present disclosure. As previously mentioned, the pivots 2207 allows the head of the screw 2204 to pivot either along the spinal rod slot 2210 (shown on FIG. 22A) or perpendicular to the spinal rod slot 2210. Teeth, groove cuts, or a roughened surface 2212 may increase the grip of this interface.

FIG. 23 illustrates a monoaxial screw 2300 in accordance with particular embodiments of the present disclosure. The monoaxial screw 2300 combines a screw head (e.g., head 2208 shown on FIG. 22A) with the bone screw portion 2304 into a single component to form the monoaxial screw 2300.

FIG. 24A illustrates a clamp assembly 2400 in accordance with particular embodiments of the present disclosure. The clamp assembly 2400 may include a spherical screw head 2402 of a bone screw 2404 that is splined. The splines on the spherical head 2402 of the bone screw may be cut to follow the spherical profile of the spherical head. The spherical screw head 2402 may be positioned into the tulip 2406 via an opening 2407 at a bottom 2408 of the tulip 2406. The spinal rod 118 may be compressed between a locking cap 2410 and a saddle 2412. The opening 2407 may include conical splines 2409 to mate with splines (e.g., splines 2403 shown on FIG. 24B) of the spherical screw head 2402.

FIG. 24B illustrates a top view of the spherical screw head 2402 in accordance with particular embodiments of the present disclosure. The splines 2403 on the spherical screw head 2402 includes a circular profile and may mate with similarly shaped splines 2409 cut into the opening 2407 (shown on FIG. 24A). These splines 2403 do not allow the tulip 2402 to rotate about the bone screw 2404, but permit medial and lateral angulation. Axial torque can be transmitted to the bone screw 2404, allowing the bone screw 2404 to be driven or reversed without engaging a drive feature, (e.g., drive feature shown on FIGS. 4A and 4B) or by an instrument (not shown) not positioned coaxially with the bone screw.

Various instrument interfaces may be used for engaging insertion, positioning, reduction, and derotation instruments. The bone screw (e.g., the bone screw 2404) may include a hex, hexalobe, or modified hexalobe in the spherical screw head for driving the bone screw into a bone. Features on the tulips in the embodiments below may be engaged by instruments with corresponding tabs or grooves which collapse, pivot, slide, or flex into engagement with the tulip for insertion, positioning, reduction, and derotation.

FIG. 25A illustrates an inner surface 2500 a of a tulip (e.g., similar to the tulip 102 shown on FIG. 1 ) in accordance with particular embodiments of the present disclosure. In this embodiment cylindrical, elliptical, or linear grooves 2502 a may be cut into the inner surface 2500 a to receive a instrument (not shown).

FIG. 25B illustrates an inner surface 2500 b of a tulip (e.g., similar to the tulip 102 shown on FIG. 1 ) in accordance with particular embodiments of the present disclosure. In this embodiment cylindrical, elliptical, or linear grooves 2502 b may be cut into the inner surface 2500 b to receive a driving instrument (not shown). As shown, the linear grooves 2502 b are smaller (e.g., shorter and/or shallower) in size than the linear grooves 2502 a of FIG. 25A.

FIG. 26A illustrates a tulip 2600 in accordance with particular embodiments of the present disclosure. The tulip 2600 may include an upper outer section 2602 a that includes a ledge, lip, or groove 2604 a, as shown.

FIG. 26B illustrates a portion 2606 a of a tulip (e.g., similar to the tulip 2600 shown on FIG. 26A) in accordance with particular embodiments of the present disclosure. The portion 2606 a may include an upper outer section 2602 b that includes a lip 2604 b and a groove 2608 a that includes an upper surface 2609 a that is angled inward, as shown. A bottom surface 2610 a is horizontal. The inward angle prevents disengagement of an instrument (not shown) under axial reduction loads.

FIG. 26C illustrates a portion 2606 b of a tulip (e.g., similar to the tulip 2600 shown on FIG. 26A) in accordance with particular embodiments of the present disclosure. The portion 2606 b may include an upper outer section 2602 c that includes the lip 2604 b and a groove 2608 b that includes the upper surface 2609 a that is angled inward, as shown. A bottom surface 2610 b is angled outward. The inward angle prevents disengagement of an instrument (not shown) under axial reduction loads.

FIG. 26D illustrates a portion 2606 c of a tulip (e.g., similar to the tulip 2600 shown on FIG. 26A) in accordance with particular embodiments of the present disclosure. The portion 2606 c may include an upper outer section 2602 d that includes a lip 2604 c and a groove 2608 c that includes an upper surface 2609 b that is flanged, as shown. The bottom surface 2610 a is flat. The flange prevents disengagement of an instrument (not shown) under axial reduction loads.

FIG. 26E illustrates a portion 2606 d of a tulip (e.g., similar to the tulip 2600 shown on FIG. 26A) in accordance with particular embodiments of the present disclosure. The portion 2606 d may include an upper outer section 2602 e that includes a lip 2604 d and a groove 2608 d that includes the upper surface 2609 b that is flanged, as shown. The bottom surface 2610 a is angled outward. The flange prevents disengagement of an instrument (not shown) under axial reduction loads.

FIG. 26F illustrates a portion 2606 e of a tulip (e.g., similar to the tulip 2600 shown on FIG. 26A) in accordance with particular embodiments of the present disclosure. The portion 2606 e may include an upper outer section 2602 f that includes the lip 2604 e and a groove 2608 e that includes the upper surface 2609 a that is angled inward, as shown. A bottom surface 2610 e is angled inward. The inward angles prevent disengagement of an instrument (not shown) under axial reduction loads.

FIG. 26G illustrates a portion 2606 f of a tulip (e.g., similar to the tulip 2600 shown on FIG. 26A) in accordance with particular embodiments of the present disclosure. The portion 2606 f may include an upper outer section 2602 g that includes the lip 2604 a without a bottom surface.

FIG. 26H illustrates a portion 2606 g of a tulip (e.g., similar to the tulip 2600 shown on FIG. 26A) in accordance with particular embodiments of the present disclosure. The portion 2606 g may include an upper outer section 2602 h that includes a lip 2604 g and a groove 2608 f that includes the upper surface 2609 b that is flanged, as shown. A bottom surface 2610 f is also flanged. The flanges prevent disengagement of an instrument (not shown) under axial reduction loads.

FIG. 26 i illustrates a portion 2606 h of a tulip (e.g., similar to the tulip 2600 shown on FIG. 26A) in accordance with particular embodiments of the present disclosure. The portion 2606 h may include an upper outer section 2602 i that includes a lip 2604 h and a groove 2608 g. A cross-section of the groove 2608 g is circular with a depth greater than the radius of the groove to prevent disengagement of an instrument (not shown) under axial reduction loads.

FIG. 26 j illustrates a portion 2606 i of a tulip (e.g., similar to the tulip 2600 shown on FIG. 26A) in accordance with particular embodiments of the present disclosure. The portion 2606 i may include an upper outer section 2602 j that includes a lip 2604 i and a groove 2608 h, as shown. A second groove 2612 may be disposed on a top of the portion 2606 i, as shown, to allow insertion of a tip of an instrument (not shown) to resist outward splaying forces under axial reduction loads.

FIG. 26K illustrates a section view of an upper portion of FIGS. 26B-J in accordance with particular embodiments of the present disclosure. As shown, upper portion 2614 which may include the upper portion 2604 c and/or 2604 d may be cylindrical.

FIG. 27 illustrates a tulip 2700 in accordance with embodiments of the present disclosure. The tulip 2700 may be similar to the tulip 102 (shown on FIG. 1 ). The tulip 2700 may include front portions 2702 a and 2702 b that include vertical slots 2704 a and 2704 b which are engaged by corresponding tabs on an instrument. A rear portion (not shown) may be similar to the front side (shown).

FIG. 28 illustrates a tulip 2800 in accordance with embodiments of the present disclosure. The tulip 2800 may be similar to the tulip 102 (shown on FIG. 1 ). The tulip 2800 may include side portions 2802 a and 2802 b. The side portion 2802 a includes a circular pocket 2804 a which is engaged by corresponding tabs on an instrument. The side portion 2802 b may be similar to the side portion 2802 a.

FIG. 29 illustrates a tulip 2900 in accordance with embodiments of the present disclosure. The tulip 2900 may be similar to the tulip 102 (shown on FIG. 1 ). The tulip 2900 may include side portions 2902 a and 2902 b. The side portion 2902 a includes a chevron which is engaged by corresponding tabs on an instrument. The side portion 2902 b may be similar to the side portion 2902 a.

FIG. 30 illustrates a tulip 3000 in accordance with embodiments of the present disclosure. The tulip 3000 may be similar to the tulip 102 (shown on FIG. 1 ). The tulip 3000 may include a threaded upper portion 3002 that may be extended to allow a spinal rod (e.g., the spinal rod 118 shown on FIG. 13 ) to be captured and reduced into the tulip 3000 by threading a locking cap (e.g., the threaded locking cap 114 shown on FIG. 1 ). Internal and/or external grooves 3004 a-3004 f allow for extended tabs 3006 a-3006 h to be broken away from the tulip 3000 once they are no longer needed. The multiple grooves 3004 a-3004 f at different heights allow tabs 3006 a-3006 h to be broken at a desired height to reduce the amount of turns necessary to turn the locking cap, or prevent contact with adjacent implants.

FIG. 31A illustrates a tulip 3100 in accordance with embodiments of the present disclosure. The tulip 3100 may be similar to the tulip 3000 (shown on FIG. 30 ). In this embodiment, a hole 3102 through a side of a tab 3006 i allows for passage of a cable 3104. When looped around the spinal rod 118 or a mating instrument 3106, tensioning of the cable 3104 reduces the spinal rod 118 into the tulip 3100 before being captured by a locking cap 3108. In certain embodiments, the holes 3102 may be in sides 3103 of the tulip 3100 without the tab 3006 i.

FIG. 31B illustrates a close-up of the tulip 3100 in accordance with embodiments of the present disclosure. As shown, the cable 3104 is positioned about the spinal rod 118 and extends through the tulip 3100.

The present disclosure as described above describes many features which allow improved functionality, strength, and ease of manufacturing for a pedicle screw head. The locking cap designs describe thread geometries that improve strength, reduce outward splaying forces on the screw head, increase resistance to cross-threading, allows quick engagement of the locking cap, a more consistent interface with mating instruments, and contacts with the spinal rod to increase gripping strength. The internal component designs describe multiple features to al low simplified geometries to reduce profile, increase polyaxial strength, and simplify manufacturing and assembly. The uniplanar, monoaxial, and axially constrained polyaxial screw designs allow for rigidity in various directions to allow the user to transmit forces to the vertebral body for correction or screw insertion. The instrument interfaces describe a variety of features to allow instruments to interface from several directions, provide increased holding strength, decrease splaying forces which would cause disengagement of instruments, and simplify manufacturing. The reduction tab designs allow for a new method for reducing the rod into the screw head.

It is believed that the operation and construction of the present disclosure will be apparent from the foregoing description. While the apparatus and methods shown or described above have been characterized as being preferred, various changes and modifications may be made therein without departing from the spirit and scope of the disclosure as defined in the following claims. 

What is claimed is:
 1. A clamp assembly comprising: a tulip comprising an opening comprising an inner surface, wherein the inner surface is threaded; a threaded locking cap disposed in the opening; a saddle configured to be positioned within the tulip, the saddle having flat portions corresponding with flat portions on the tulip, to restrict rotation of the saddle, wherein the diameter of an upper portion of the saddle including the flat portions is smaller than the diameter of a lower portion of the saddle; and a clip positioned within a groove on a bottom portion of the tulip, wherein the clip retains a head of screw within the clamp assembly, a driving instrument having a distal end with spring tabs; a rod positioned within the tulip and positioned over the saddle; wherein the threaded locking cap includes grooves for receiving the spring tabs of a driving instrument, wherein the spring tabs are configured to clip into the grooves of the locking cap to secure the driving instrument to the locking cap.
 2. The clamp assembly of claim 1, wherein top surfaces of threads of the inner surface are rectangular and wherein bottom surfaces of threads of the inner surface are angled.
 3. The clamp assembly of claim 2, wherein top surfaces of threads of the threaded locking cap are rectangular and wherein bottom surfaces of threads of the locking cap are angled.
 4. A clamp assembly comprising: a tulip comprising an opening comprising an inner surface, wherein the inner surface is threaded; and a threaded locking cap disposed in the opening, wherein the threaded locking cap includes a drive feature, a saddle configured to be positioned within the tulip, the saddle having flat portions corresponding with flat portions on the tulip, to restrict rotation of the saddle wherein the diameter of an upper portion of the saddle including the flat portions is smaller than the diameter of a lower portion of the saddle; and a clip positioned within a groove on a bottom portion of the tulip, wherein the clip retains a head of screw within the clamp assembly, a driving instrument having a distal end with spring tabs; a spinal rod positioned within the tulip and positioned over the saddle; wherein the drive feature of the threaded locking cap includes grooves for receiving spring tabs of a driving instrument, wherein the spring tabs are configured to clip into the grooves of the locking cap to secure the driving instrument to the locking cap.
 5. The clamp assembly of claim 4, wherein a bottom of the threaded locking cap comprises a tapered flat portion.
 6. The clamp assembly of claim 5, wherein a bottom of the threaded locking cap comprises a rounded bump.
 7. The clamp assembly of claim 6, wherein a bottom of the threaded locking cap comprises a rounded ring configured to contact the spinal rod at two points.
 8. The clamp assembly of claim 6, wherein a bottom of the threaded locking cap comprises a groove configured to seat on the spinal rod.
 9. The clamp assembly of claim 6, wherein a bottom of the threaded locking cap comprises a contact component made of a different material than the threaded locking cap.
 10. The clamp assembly of claim 6, wherein an outer surface of the tulip comprises grooves configured to receive a driving instrument.
 11. A clamp assembly comprising: a tulip, wherein an inner surface of the tulip comprises threads; and a drive feature positioned in an outer portion of the tulip, the drive feature configured to receive a driving instrument a threaded locking cap disposed in the opening; a saddle configured to be positioned within the tulip, the saddle having flat portions corresponding with flat portions on the tulip, to restrict rotation of the saddle wherein the diameter of an upper portion of the saddle including the flat portions is smaller than the diameter of a lower portion of the saddle; and a clip positioned within a groove on a bottom portion of the tulip, wherein the clip retains a head of screw within the clamp assembly, a driving instrument having a distal end with spring tabs; a rod positioned within the tulip and configured to contact the saddle; wherein the threaded locking cap includes grooves for receiving spring tabs of a driving instrument, wherein the spring tabs are configured to clip into the grooves of the locking cap to secure the driving instrument to the locking cap.
 12. The clamp assembly of claim 11, wherein the feature comprises a pocket in a shape of a chevron, a vertical slot, or a circle. 